Survival and behavioural responses of cool and warm water fish sedated with AQUI-S®20E (10% eugenol) at high loading densities

This study evaluated the effects of AQUI-S (R) 20E (10% eugenol) sedation on the survival and behaviour of yellow perch Perca flavescens (Mitchill) and Nile tilapia Oreochromis niloticus L. held in high loading densities. Fish were held in 0-300 mg L-1 AQUI-S (R) 20E (0-30 mg L-1 eugenol) for up to 10 h in static tanks. At 17 degrees C, yellow perch held in 200 and 300 mg L-1 AQUI-S (R) 20E were lightly sedated for up to 7 h. Yellow perch at 200 and 300 mg L-1 AQUI-S (R) 20E also had > 95% mean survival 7-days post exposure using loading densities up to 360 g L-1. Nile tilapia were only sedated for = 3 h in concentrations up to 300 mg L-1 at 22 degrees C and had > 90% mean survival at loading densities = 480 g L-1. Ammonia in tanks increased significantly as loading density increased, but treatment with AQUI-S (R) 20E did not reduce ammonia accumulation. Results suggest that AQUI-S (R) 20E was effective to sedate yellow perch and Nile tilapia at high loading densities, but sedation varied with loading density and species.